ASA-6A Tube Vari-Mu Compressor

ASA-6A - RCA BA6A Vari-Mu Compressor Clone Front Panel 2025

ASA-6A Tube Vari-Mu Compressor

$2,899.00 $3,499.00

Vintage tube compression doesn't get any better than this

An exacting, hand-built recreation of the iconic RCA BA6A variable-gain broadcast limiter introduced in 1951, now expanded with individual controls for attack, release, and threshold! Featuring nine total tubes, this rare legend is renowned for its ability to smoothly level any source, adding heft and weight unlike any other. The sound of the ASA-6A can be described as creamy and incandescent – one of the finest examples of vintage tube compression from any era.

**HASSLE-FREE 2-YEAR WARRANTY INCLUDED!
**FREE PATCHRAT PRO SUBSCRIPTION INCLUDED WITH EVERY PURCHASE! **

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History of the BA6A Limiting Amplifier

When RCA introduced its BA6A compressor in 1951, they actually cited the nine-tube design as economical, yet “high-quality”, “employing only 9 tubes…”. But it’s all those tubes and all the iron in the transformers that made it sound so great when saturated. Not so good for radio broadcasts, but incredible for the acoustic guitars on “Tangerine” from Led Zep III!

AudioScape’s ASA-6A is a faithful recreation of that all-tube variable-gain heavyweight from the early 1950’s. The thickness and weight it imparts is due partly to the monstrous amount of gain it adds. But, owing to its variable-gain design, the compression never suffocates the track, even with all that gain. The ratio increases only as the input gain increases, giving it a gentle, soft-knee slope. But the harder you hit it, the thicker it gets.

ASA-6A: New Modern Features

The core circuit of the ASA-6A is faithful to the RCA original down to the NOS tubes and Hammond transformers throughout. We’ve added some new modifications to expand the versatility of this amazing circuit even further, such as:

Individual attack, release, and threshold controls for better control of dynamics - each with “stock” settings marked to match the original if desired
“NFB” front panel switch to drive the entire circuit with an additional +5dB of gain by reducing negative feedback
“OFF” position on BAL-LIM rotary switch to bypass limiting and drive the the all-tube line amplifier by itself

This compressor is truly one of the finest examples of vintage vari-mu tube circuitry ever built. We think you’ll love it as much as we do!

Shipping Info & Lead Times

Shipping within the contiguous United States
International Shipping available during checkout
Hassle-free 2-year warranty included

Current Lead Time: 3-4 weeks*

*Please allow an additional 2 weeks for matched pairs.

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FEATURES & SPECS:

Handcrafted in the USA
NFB toggle switches between the original "Stock" mode and the new "Drive" mode, which boosts input gain by 5dв
3 Time-Constant options via the BAL-Limit rotary switch: Single or Dual, or Off, which bypasses the compressor entirely, but still passes a fat signal through all those tubes
Custom 20 position stepped Input and Output Controls, tweaked for maximum usable range; allowing for countless saturation options
Attack, Release and Threshold controls added with stock BA-6A designations on each scale plate
120 Hz Sidechain HPF for more nuanced triggering
PIO AUDIO Capacitors
Allen-Bradley carbon comp resistors in key areas of the signal path
Period correct knobs
Umber Gray front panel with vintage style scale plates
Electronically Balanced +4dBu circuitry
Custom stepped switches, Allen Bradley and Alpha pots
Custom Vintage-Styled Lighted VU Gain-Reduction Meter
Neutrik® XLR Input and Output Connectors
Dual Primary 120V/240V Power Supply (prewired for region of purchase)
**specifications, parts & pricing subject to change because sh*t happens ;-)